Method for producing streams of fireextinguishing dry chemical



R 216999216 SR A. ALLEN METHOD FOR PRODUCING STREAMS 0FFIRE-EXTINGUISHING DRY CHEMICAL Filed Jan. 31 1951 IN VEN TOR. A N ALLENA *TTORNEY United States Patent M METHOD FOR PRODUCING STREAMS OF FIRE-EXTINGUISHING DRY CHEIVIICAL Alden Allen, Menominee, Mich., assignor toAnsul Chemical Company, Marinette, Wis., a corporation of WisconslnApplication January 31, 1951, Serial No. 208,826

2 Claims. (Cl. 169-1) This invention relates to a method for producingstreams of powdered fire-extinguishing dry chemical of predeterminedvelocity, shape, and range.

It is now generally recognized that flammable liquids and gases whenafire can be effectively extinguished by means of finely powdered drychemical composition containing sodium bicarbonate as the essentialingredient, as disclosed for example in Patent 1,793,420 February 17,1931. Such dry chemical is usually fluidized in a storage container bymeans of an inert gas, such as nitrogen, supplied at a pressure of about2000 lbs. per square inch. The fluidized dry chemical is then expelledfrom the container at a pressure of about 200 to 250 lbs. per squareinch through suitable hose lines provided with nozzles for extinguishingthe fire. The hose may be held and manipulated manually whenextinguishing a fire or in some instances the nozzle may be supported ona turret mounted on a moving vehicle which is brought to the site of thefire or aboard ships and other structures. It has been found that it isoften important to be able to continuously control the shape, velocity,and range of the expellant dry chemical stream in effectivelyextinguishing a fire depending upon the extent and character of the fireinvolved.

The nozzles with single orifices which have been hitherto available foremitting streams of dry chemical usually can emit only a fixed type ofstream and the fire fighter is therefore limited in his mode ofextinguishing a given fire and may lose time in the early criticalperiod of a fire in adjusting this technique, position, and distancerelative to the fire in order to extinguish it in the shortest period oftime with the fixed type of stream. The character of a fire may alsochange either in intensity or extent after a fire-extinguishing streamis directed on a fire so that it may become neces sary for the firefighter to readjust his fire-fighting technique or to change hisposition relative to the fire.

The present invention overcomes the difiiculties previously mentioned byproviding an adjustable nozzle for continuously producing streams offire-extinguishing dry chemical of predetermined velocity, shape andrange so that the fire fighter can have available instantly the type ofdry chemical stream best suited for his need in extinguishing the firehe is coping with, depending upon its character from moment to momentuntil it is finally extinguished.

Further advantages and objects of the invention will be apparent fromthe following specification and drawings, wherein Figure 1 is anenlarged longitudinal partial sectional view of an adjustable telescopicnozzle constructed in accordance with the present invention,

Figure 2A is a view of the telescopic nozzle shown in Figure 1 in fullycollapsed position for producing a predetermined relatively low velocitystream of dry chemical which is relatively wide in cross-section andshort in range,

Figure 2B is a view of the telescopic nozzle shown in Figure l inpartially extended condition for producing a relatively high velocitydry chemical stream which has a long range and which is relativelynarrow in cross-section, and

Figure 2C is a view of the nozzle shown in Figure 1 in its fullyextended position to produce a dry chemical stream which is relativelynarrow in cross-section, of short range, and low velocity.

2,699,216 Patented Jan. 11, 1955 take end of nozzle tube 10 is suitablyconnected to a conduit supplying fluidized dry chemical supplied under aconstant expelling gas pressure, as for example 200 to 250 lbs. persquare inch. The supply conduit should have a cross-sectional area equalto or greater than the cross-sectional intake end of nozzle tube 10.

A second tube 11, of smaller diameter than tube 10, is slidably retainedin tube 10 by retaining rings 17 and 19. A suitable compressible sealingring 16 serves to seal the end of tube 11. A sealing ring 20 serves toseal the forward end of tube 10 in slidable relation to the innersurface of tube 11 and to support tube 11 for slidable support thereon.

Tube 12 is slidably retained in tube 11 in telescoped relation theretoby means of retaining rings 18, 21 and 23. A sealing and supporting ring24 is provided adjacent the inner end of tube 12 for sealing the outerface of tube 12 in slidable engagement with tube 11.

The nozzle tube sections 11 and 12 can be adjustably extended axially oftube 10 to any desired length by simply sliding tubes 11 and 12 to anysuitable relative position. A nozzle of predetermined and suitablelength and diameter can thus be readily provided by the fire fighter inorder to continuously produce a stream of dry chemical havingpredetermined desired characteristics. For example, if it is desired toproduce a dry chemical stream which is relatively wide in cross-section,of relatively short range, and relatively low velocity, the nozzle tubes11 and 12 are fully retracted, as shown in Figure 2A. In this positionnozzle tube 12 will be retracted until retaining ring 23 engages theouter face of tube 11. The two nozzle tubes 11 and 12 are then retractedtogether until retaining ring 25 engages the face of tube 10 in itsrearmost position. When a stream of dry chemical is fed to the nozzle ofsuch length, the fluidizing and expellant gas of the dry chemical streamwithin the nozzle tube 12 has not fully expanded when it leaves thenozzle and enters the atmosphere. The expansion of the gas at the nozzletip will cause the escaping stream A to spread out so that it attains arelatively wide cross-sectional shape, as shown in Figure 2A, and at thesame time its forward velocity is reduced so that the stream has arelatively short range. It is thus apparent that the length of the fullycollapsed nozzle is selected for a given supply of fluidized drychemical and pressurized at a given pressure so as to produce a drychemical stream of maximum width, short range, and low velocitv.

Similarly, it is possible to obtain a dry chemical stream having amaximum long range. minimum width in crosssection, and relatively highvelocity by using a single nozzle tube of predetermined length anddiameter or an extended telescopic nozzle of such length and diameterthat when the stream of dry chemical leaves the nozzle the fluidizingand pressurizing gas in the stream will have ex anded substantially toits maximum amount in the tube so that it substantially equals theprevailing atmospheric pressure. Under such conditions, the dry chemicalwill have attained its maximum velocity when it is ejected from thenozzle thereby producing a dry chemical stream of maximum long range andminimum width in cross-section. Such nozzle is shown in Figure 2Bwherein nozzle tubes 11 and 12 are moved forwardly in relation to tube10 so as to emit a stream B from the nozzle 12.

It will be apparent that a dry chemicalstream of any predeterminedcharacteristics intermediate the maximum and minimum ranges andcross-section width can be obtained by either using a nozzle tube ofsuitable diameter and length or by continuously adjusting the telescopicnozzle tubes to the desired length. For example, when it is desired toproduce a dry chemical stream of relatively narrow cross-section, lowvelocity, and short range, the nozzle tubes 11 and 12 are fully extendedto their maximum length relative to tube 10, as shown in Figure 2C. Inthis condition the fiuidizing and pressurizing gas in the dry chemicalstream will expand to substantially atmospheric pressure while stillwithin the nozzle tube and thereafter will continue moving forwardlywithin the nozzle so that as a result of friction losses within the tubethe forward velocity of the stream will be reduced to such extent thatthe stream C issuing from nozzle will be relatively narrow incross-section and of short range.

The present invention thus provides a method and means of producing drychemical streams having any desired predetermined characteristics byeither selecting a nozzle tube of suitable diameter and length or byadjusting the length of the nozzle when using a telescopic type ofnozzle, as previously described, so that the continuous stream producedwill have the desired velocity, range and shape which may be required toextinguish any type of fire as the circumstances may occur. According tothe present method it is possible to feed continuously a stream offluidized dry chemical through a nozzle tube of predeterminedcross-section and length to control expansion of the expellant gaswithin the tube to a predetermined value, then expelling the stream intothe atmosphere to produce a stream of predetermined cross-section shapeand range, depending upon the extent of the expansion of the expellantgas at the point where it enters the open atmosphere.

Modifications and changes may be made of the described details andprocedures of this invention which are intended to be included withinthe scope of the appended claims.

I claim:

1. A method of producing a fire-extinguishing dry chemical stream havinga predetermined cross-sectional shape, velocity and range whichcomprises continuously passing a fluidized stream of dry chemical underpropellant gas pressure substantially greater than atmospheric pressurethrough a confined zone opening to the atmosphere of predeterminedlength and cross-sectional area to permit the propellant gas pressure toissue into the atmosphere at a pressure greater than atmosphericpressure at the point of entry of said stream into the atmosphere topermit secondary expansion of said stream outside of said confined zoneto produce an emitted dry chemical stream relatively wide incross-section and of reduced forward velocity and relatively shortrange, and adjusting the ratio of the cross-sectional area and thelength of the said confined zone while the stream is flowingcontinuously to reduce secondary expansion of said stream outside ofsaid confined zone and to produce an emitted dry chemical stream ofmaximum range and velocity and relatively narrow cross-section.

2. A method of producing a fire-extinguishing dry chemical stream havinga predetermined cross-sectional shape, velocity and range whichcomprises continuously passing a fluidized stream of dry chemical underpropellant gas pressure substantially greater than atmospheric pressurethrough a confined zone opening to the atmosphere of predeterminedadjusted ratio of the cross-sectional area and length for controllingthe expansion of the propellant gas pressure within said confined zoneto a predetermined pressure prior to entry of said stream into theatmosphere to produce an emitted dry chemical stream of desiredcross-section, velocity and range, and adjusting the ratio of thecross-sectional area and the length of the said confined zone while thestream is flowing continuously to suitably alter the cross-section,velocity and range of the emitted dry chemical stream.

References Cited in the file of this patent UNITED STATES PATENTS129,167 Reynard July 16, 1872 1,370,252 Williams Mar. 1, 1921 2,078,580Moore Apr. 27, 1937 2,484,942 Guise Oct. 18, 1949

